Hello I have a 29 gallon FOWLR with a large clownfish, yellow tail damsel, lionfish, and diamond goby. For Xmas I got a 750 gph power head I had it on for about 3 hours before I realized the fish hated it and when I woke up the next day the goby was dead and all of my other fish did not look good when I woke up 2 days after that all of my fish were dead... If I could get any help understanding what I did wrong would be great so I wont do it again.